import pandas as pd  

df1=pd.DataFrame({'A':[1,2,3],'B':[4,5,6],'C':[7,8,9]})
print(df1)

#method1,直接重新命名df1的列名
df1.columns=['a','B','c']  
print('method1:\n',df1)

#method2,指定修改某列或某幾列名字,是否用'inplace'參數的差別
'''no_inplace'''
df1.rename(columns={'a':'A','b':'B'}) 
print('method2_no_inplace:\n',df1)
'''inplace'''
df1.rename(columns={'a':'A','b':'B'},inplace=True) 
print('method2_inplace:\n',df1)

df1.rename(columns={'c':'D'},inplace=True) 
print('修改一個列名\nmethod2_inplace:\n',df1)